1. Field of the Invention
The invention relates to a power wrench with a motor supported in a housing and drivingly connected to an output shaft via a reduction gearing, including a separate gearing casing swivel connected to the housing.
2. Description of Related Art
In particular the invention concerns a power wrench of the above type intended to have a torque reaction bar rigidly attached to a separate swivelling gearing casing for taking support on a stationary object in the vicinity of the screw joint being tightened, wherein the swivel connected gearing casing is intended to be rotated to obtain a proper support position for the reaction bar. A power wrench of this type is described in U.S. Pat. No. 4,485,698.
Normally, power wrenches with a reduction gearing have torque sensing means provided between a ring gear of a planetary reduction gearing and the housing to indicate the reaction torque of the gearing. However, in the above described type of power wrench having a rotatable gearing casing there is a problem and a difficulty to connect electrically a torque transducer located in the rotatable gearing casing with conductors in the tool housing. A torque transducer also tends to increase the external dimensions of the gearing casing which is disadvantageous as regards accessibility and handling of the wrench.